Those who are not blind have
an idea of color because they have had sense impressions of color.

This applies only to simple ideas. We can mentally
construct complex ideas (e.g., of the New Jerusalem) out of simple ideas.

Complex ideas can be
analyzed into their component parts, which are ultimately single sense
impressions.

For Hume knowledge is based on sense impressions, or
sense-perception.

Sense impressions are more “vivid,” more “lively,” more “forceful
than ideas.

The
sense impression of “red” is more vivid than the idea of “red.”

For Hume ideas are epistemologically inferior to
impressions.

Here Hume goes against the
Platonic tradition. For Plato ideas are more vivid than sense impressions.

For Plato “ideas” are the
proper object of study. “Ideas come first, for Plato.

Hume reverses this. Singular
sense perceptions come first.

This is how Hume attacks metaphysics. (257)

If an idea does not come
from a simple, single sense impression, then it is meaningless.

Hume uses this reasoning to criticize the relation of
cause and effect.

On
Cause & Effect (Kenny, pp. 260-263)

Western philosophers and scientists
traditionally believed that to know something fully one must know the cause
upon which it necessarily depends. Hume argues that such knowledge is
impossible.

Remember that,
for Hume, knowledge is grounded in single sense impressions.

“Redness” can be
an inherent quality of objects (like “This apple is red”) but “causation” cannot
be any particular inherent quality of objects. (260)

Every effect must have a cause. But this does not mean
that every event is an effect.

What do our senses tell us? We see are “relationships
between objects.”

We see that causes and
effects must be contiguous (next) to each other.

We see
that causes must be prior to their effects.

But Hume denied that there
must be a necessary connection between cause and effect.

This is because I can think of an effect without thinking of
a cause of it. If there was a necessary connection between cause and effect
I would not be able to think of an effect without thinking of its cause, just
as I cannot think of a triangle without thinking of it as having three sides,
necessarily.

NOTE: I cannot think of a
triangle that does not have 3 sides. ‘3-sidedness’ is necessarily connected
with the idea of a ‘triangle.’

But
I can think of an effect without a cause.

I can think of the pizza on
the table without thinking of what caused it to come into being.

Therefore there is no
necessary connection between cause and effect.

“There is no absurdity in conceiving something coming
into existence, or undergoing a change, without any cause at all.”

There is therefore no
absurdity in conceiving of an event occurring without a cause of some
particular kind.

Hume writes:

“As all distinct ideas are
separate from each other, and as the ideas of cause and effect are evidently
distinct, it will be easy for us to conceive any object to be non-existent
this moment, and existent the next, without conjoining to it the distinct idea
of a cause or productive principle.” (260)

“Hume’s
answer is that the observation of the resemblance produces a new impression in the mind.” (261)

Once we have observed a
number of instances of B following A, we feel a determination of the mind to pass
from A to B.

“It is here that we find the
origin of the idea of necessary connection. Necessity is ‘nothing but an
internal impression of the mind, or a determination to carry our thoughts from
one object to another.’”

Customary conjunction
produces an impression in our mind that, when we see the cause, we expect the
effect. This is where the idea of “necessary connection” is derived.

In Hume we have three new “principles of great
importance.”

1.Cause
and effect must be distinct existences, each conceivable without the other.

2.The
causal relation is to be analyzed in terms of contiguity, precedence, and
constant conjunction.

a.Closeness

b.Prior
to (in time)

c.Always
together

3.It
is not a necessary truth that every beginning of existence has a cause.

a.Because
I can think of effects without also thinking of their causes.

Kenny writes: “To this day
the agenda for the discussion of the causal relationship is the one set by
Hume.” (262)

SUMMARY

The causal relationship between any two objects is based
on experience.

What does experience tell
us? Only that the cause is prior in time and contiguous with its effect.

Experience DOES NOT
establish a necessary connection between cause and effect. Because we can
imagine the effect without also thinking of the cause.

We think there is something in the cause that produces
the effect. This is a mistake.

Our past
experiences have habituated us to think that way.

We have seen in
the past thatB often followsA and
never occurs without it, our mind associatesB withA such
that the presence of one determines the mind to think of the other.